Tuesday, August 04, 2009

 

Fruits and vegetables are great sources of antioxidants

What food has the highest antioxidant content? I am not going to tell you and it probably does not matter.

Antioxidants are found in all plant foods. There are numerous antioxidant compounds -- thousands have been identified including Beta-carotene, Vitamin C, Vitamin E, Selenium, and phytochemicals such as lycopene, lutein, flavonoids, reversitol, anthocyanins.

An orange contains at least 170 known different antioxidants. They are concentrated in the pulp and skins of plants, so whole foods would have a higher concentration than juices or peeled foods.

Some antioxidants are broken down by cooking and heat and some are released from the plant cells by cooking. A good example of this is lycopene in tomatoes.

What is an antioxidant? Antioxidants protect plants for oxidative damage from the sun, damage by insects and from oxygen made inside the plant through photosynthesis.

People are not plants, but antioxidants help them too. The cells in your body burn oxygen, producing free radicals. These are not escaped hippies, but rather unstable molecules that can cause damage to cells and DNA. Antioxidants sweep up these unstable molecules and render them harmless. Ultra violet light and smoking also produce free radicals.

When you cut an apple in half and it turns brown, this is damage from the oxygen in the air to the apple. If you dip the apple in orange juice, the apple will stay white, this happens because the Vitamin C in the orange juice protects the cells of the apple from damage.

Many locally grown and common foods are good sources of antioxidants: Delicious Granny Smith apples, cherries, blueberries, pecans, potatoes (skin on) and dried beans.
Herbs, spices, coco, nuts and tea are also good sources of antioxidants.

Antioxidants are measured in the lab, getting an ORAC rating (oxygen radical absorption capacity).

Each lab’s method differs, making ORAC values vary. ORAC values are based on 100 grams (3.5 ounces of food), not on commonly consumed amounts or recommended portion sizes.

ORAC value of Acai berries is based on a freeze-dried product weighing 100 grams. Think about how much popcorn it would take to weigh 3.5 ounces (about 3 1⁄2 cups); that is why the ORAC value is so high, a huge amount of berries are being measured. Another problem with ORAC ratings is that is does not measure actually usability in the body.

There is much that we do not know about antioxidants. We do not know how much antioxidants per day are needed to prevent disease.

Antioxidants have been linked with lower rates of heart disease, eye health and some types of cancer. We also do not know if the effects are related to the antioxidants alone or the whole plant food.

Fruits, vegetables, whole grains, nuts and seeds have value beyond antioxidant content; they are good sources of dietary fiber, vitamins, minerals and fatty acids. These whole food components likely work together. For this reason getting antioxidants in a pill or supplement form is probably not as beneficial as getting antioxidants from whole foods.

Get your antioxidants by eating whole plant foods and whole grains. Aim for more than five servings of fruits and vegetables per day with an optimal goal of seven servings per day.

Vary the types and colors of plant based foods that you eat. Antioxidant value of processed foods (flavored beverages and yogurts) containing added antioxidants and fruit extracts are more of a marketing ploy than a healthy addition to your menu. Many of these products are high is sugars and calories and just plain do not taste as wonderful as a fresh ripe watermelon or sugar snap peas. Instead enjoy plain yogurt with a fresh peach, a sprinkling of walnuts and a teaspoon of honey.

Homemade iced tea with lemon is a good choice for an antioxidant-rich cold drink. Fill your plate with rainbow colors; greens (kale, broccoli, kiwi) orange (carrots, squash, cantaloupe) yellow (grapefruit, yellow beans) purple (eggplant, plums, blueberries), red (tomatoes, watermelon, cranberries) and white (cauliflower, apples, onions).

Mary Beth Dahlstrom Green is a dietitian at The William W. Backus Hospital. This column should not replace advice or instruction from your personal physician. E-mail Green and all of the Healthy Living columnists at healthyliving@wwbh.org or comment on their blog at healthdocs.blogspot.com.

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